import java.sql.*;
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        //m1();
        //m2();
        //m3();
        //m4();
        m5();
    }

        private static void m1() {
            Connection root = null;
            PreparedStatement preparedStatement = null;
            ResultSet resultSet = null;

            //jdbc
            //1，加载驱动
            try {
                Class.forName("com.mysql.cj.jdbc.Driver");
                //2.创建链接
                String url = "jdbc:mysql://127.0.0.1:3306/jdbc?characterEncoding=utf-8";
                root = DriverManager.getConnection(url, "root", "123456");
                if (root != null) {
                    System.out.println("连接成功");
                }

                //3，写sql
                String sql = " SELECT * FROM `user`";


                //4，预编译sql
                preparedStatement = root.prepareStatement(sql);

                //5，执行sql
                resultSet = preparedStatement.executeQuery();

                //6，遍历结果
                while (resultSet.next()) {
                    int id = resultSet.getInt(1);
                    String name = resultSet.getString(2);
                    String pass = resultSet.getString(3);
                    System.out.println(id + "....." + name + "....." + pass);
                }


            } catch (ClassNotFoundException e) {
                throw new RuntimeException(e);
            } catch (SQLException e) {
                throw new RuntimeException(e);
            } finally {
                //7.关闭资源
                try {
                    if (resultSet != null) {
                        resultSet.close();
                    }
                    if (preparedStatement != null) {
                        preparedStatement.close();
                    }
                    if (root != null) {
                        root.close();
                    }
                } catch (SQLException e) {
                    throw new RuntimeException(e);
                }
            }
        }

        private static void m2() {
            //键盘录入
            Scanner scanner = new Scanner(System.in);
            System.out.println("请输入要查询的用户名：");
            String name = scanner.nextLine();
            Connection root = null;
            PreparedStatement preparedStatement = null;
            ResultSet resultSet = null;
            //jdbc
            //1，加载驱动
            try {
                Class.forName("com.mysql.cj.jdbc.Driver");
                //2.创建链接
                String url = "jdbc:mysql://127.0.0.1:3306/jdbc?characterEncoding=utf-8";
                root = DriverManager.getConnection(url, "root", "123456");
                if (root != null) {
                    System.out.println("连接成功");
                }

                //3，写sql
                String sql = " SELECT * FROM `user` where name like ? ";
                //4，预编译sql
                preparedStatement = root.prepareStatement(sql);
                //设置参数
                preparedStatement.setString(1, "%" + name + "%");
                //5，执行sql
                resultSet = preparedStatement.executeQuery();

                //6，遍历结果
                while (resultSet.next()) {
                    int id = resultSet.getInt(1);
                    String username = resultSet.getString(2);
                    String pass = resultSet.getString(3);
                    System.out.println(id + "....." + username + "....." + pass);
                }


            } catch (ClassNotFoundException e) {
                throw new RuntimeException(e);
            } catch (SQLException e) {
                throw new RuntimeException(e);
            } finally {
                //7.关闭资源
                try {
                    if (resultSet != null) {
                        resultSet.close();
                    }
                    if (preparedStatement != null) {
                        preparedStatement.close();
                    }
                    if (root != null) {
                        root.close();
                    }
                } catch (SQLException e) {
                    throw new RuntimeException(e);
                }
            }
        }
        private static void m3() {
        Scanner Sc = new Scanner(System.in);
        Connection root = null;
        PreparedStatement preparedStatement = null;

        //jdbc
        //1，加载驱动
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
            //2.创建链接
            String url = "jdbc:mysql://127.0.0.1:3306/jdbc?characterEncoding=utf-8";
            root = DriverManager.getConnection(url, "root", "123456");
            if (root != null) {
                System.out.println("连接成功");
            }
            //3，写sql
            String sql = " insert into user(name,pass) values (?,?)";
            //4，预编译sql
            preparedStatement = root.prepareStatement(sql);
            //设置参数
            String a = Sc.next();
            String b = Sc.next();
            preparedStatement.setString(1, a);
            preparedStatement.setString(2, b);
            //执行增加
            int result = preparedStatement.executeUpdate();
            if (result > 0){
                System.out.println("增加成功");
            }else {
                System.out.println("增加失败");
            }
            //5，执行sql
        } catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        } finally {
            //6.关闭资源
            try {
                if (preparedStatement != null) {
                    preparedStatement.close();
                }
                if (root != null) {
                    root.close();
                }
            } catch (SQLException e) {
                throw new RuntimeException(e);
            }
        }
    }
        private static void m4() {
        Scanner Sc = new Scanner(System.in);
        Connection root = null;
        PreparedStatement preparedStatement = null;

        //jdbc
        //1，加载驱动
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
            //2.创建链接
            String url = "jdbc:mysql://127.0.0.1:3306/jdbc?characterEncoding=utf-8";
            root = DriverManager.getConnection(url, "root", "123456");
            if (root != null) {
                System.out.println("连接成功");
            }
            //3，写sql
            String sql = "update user set name = ?,pass = ?where id = ?";
            //4，预编译sql
            preparedStatement = root.prepareStatement(sql);
            //设置参数
            String a = Sc.next();
            String b = Sc.next();
            int c = Sc.nextInt();
            preparedStatement.setInt(3, c);
            preparedStatement.setString(1, a);
            preparedStatement.setString(2, b);

            //执行增加
            int result = preparedStatement.executeUpdate();
            if (result > 0){
                System.out.println("修改成功");
            }else {
                System.out.println("修改失败");
            }
            //5，执行sql
        } catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        } finally {
            //6.关闭资源
            try {
                if (preparedStatement != null) {
                    preparedStatement.close();
                }
                if (root != null) {
                    root.close();
                }
            } catch (SQLException e) {
                throw new RuntimeException(e);
            }
        }
    }
        private static void m5() {
        Scanner Sc = new Scanner(System.in);
        Connection root = null;
        PreparedStatement preparedStatement = null;

        //jdbc
        //1，加载驱动
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
            //2.创建链接
            String url = "jdbc:mysql://127.0.0.1:3306/jdbc?characterEncoding=utf-8";
            root = DriverManager.getConnection(url, "root", "123456");
            if (root != null) {
                System.out.println("连接成功");
            }
            //3，写sql
            String sql = "delete from user where id = ?";
            //4，预编译sql
            preparedStatement = root.prepareStatement(sql);
            //设置参数
            String a = Sc.next();
            preparedStatement.setString(1, a);
            //执行增加
            int result = preparedStatement.executeUpdate();
            if (result > 0){
                System.out.println("删除成功");
            }else {
                System.out.println("删除失败");
            }
            //5，执行sql
        } catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        } finally {
            //6.关闭资源
            try {
                if (preparedStatement != null) {
                    preparedStatement.close();
                }
                if (root != null) {
                    root.close();
                }
            } catch (SQLException e) {
                throw new RuntimeException(e);
            }
        }
    }

}
